19. She was late to school she missed the bus.A) soB) becauseC) althoughD) when20. Bring a jacket _ it gets cold later.A) soB) althoughC) ifD) because21. They left earlythey could avoid the traffic.A) ifB) soC) becauseD) although22. I will call youI arrive at the airport.A) whenB) becauseC) although